Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Taxes [Line Items]
Income tax (benefit) expense	$ (3,000,000)	$ 1,000,000	$ (2,000,000)	$ 14,000,000
State tax benefit			(3,000,000)
Tax benefit from deferred tax liabilities	1,000,000		$ 1,000,000
Percentage of adjusted taxable income			50.00%		30.00%
Built-in gains tax expense from assets sold				14,000,000
Non-U.S. income tax expense				16,000,000
Income tax benefit partially offset by TRS				$ 20,000,000
Income tax expense (benefit) from NOL carryback	2,000,000		$ 2,000,000
U.S. Federal Tax [Member] | REIT [Member]
Income Taxes [Line Items]
Income tax (benefit) expense	$ 0		$ 0